It seems reasonable to assume that a major area of potential application of nuclear magnetic reasonance (NMR) imaging will be the brain. A major potential area of application for NMR is the detection and characterization of intracranial tumors. The aim of this proposal is to compare the sensitivity and specificity of NMR images in the detection and characterization of brain tumors as compared to nonenhanced and enhanced CT, radionuclide bruin images and radionuclide single photon emission computed tomography (SPECT). Two hundred (200) patients with central nervous system symptoms to include 100 with operated primary brain tumors will be imaged with CT, highest quality radionuclide images, SPECT, and nuclear magnetic resonance. Fifty (50) normal volunteers will also be imaged with NMR. The results will be subjected to statistical analysis to assess the relative accuracy and specificity of each imaging modality. In the second part of the proposal 20 patients having terminal metastatic cancer with multiple brain metastases will be studied with the 4 imaging modalities within 3 weeks of death. At autopsy the brains will be sectioned axially and the number, size and location of lesions carefully documented and correlated with the imaging modalities as to accuracy, resolution, and specificity.